The present invention relates to a dual-band FR4 chip antenna, and more particularly, to a dual-band chip antenna fabricated by forming a meandering radiating metal line on a chip base made of an FR4 material.
As communication technologies have been growing prosperously, various applications on the communication technologies have also been appeared in the market dramatically. In addition, the IC technologies have become more matured, so that the products can be made smaller and smaller. As to an antenna used for radiating and receiving signals in communication products, it plays a very important role in deciding if the products can achieve the goal of small size.
An antenna is an element used for radiating or receiving an electromagnetic wave. Generally, characteristics of an antenna can be determined by the parameters of radiation pattern, return loss and antenna gain. Nowadays, antennas need to have the features of small size, good performance and low cost in order to be popularly accepted by the market. According to the locations where antennas are mounted, the antennas can be classified into two categories, which are a built-in type and an external type. For the sake of appearance, the built-in typed antennas have gradually replaced the external-typed antennas. On the other hand, the surface mounting technology (SMT) that can be utilized for mass production has been quite matured. Hence, chip antennas that are suitable for using the SMT become one of the most popular designs for the built-in typed antennas, since the cost of packaging and connection thereof can be greatly reduced.
However, a conventional chip antenna is usually made of a ceramic material, and the ceramic material has the shortcomings of being expensive and fragile, so that the cost for making the ceramic chip antenna is high and the ceramic antenna is further not endurable due to its fragility. Therefore, there is an urgent need in developing a low-cost and sturdy chip antenna for: overcoming the shortcomings of the ceramic chip antenna; lowering the cost for integrating with microwave circuits; and further enhancing the product stability.
Just as described above, the conventional ceramic chip antenna is not only expensive but also fragile, causing the end product to be expensive and unendurable. Hence, the conventional ceramic chip antenna cannot be applied broadly in various products.
Therefore, it is a main object of the present invention to provide a dual-band FR4 chip antenna to replace the conventional ceramic chip antenna by using an FR4 material that is low in cost and sturdy, and to design a chip antenna having the features of low cost, good performance and sturdiness, wherein the chip antenna can be fabricated in different patterns and forms in accordance with actual needs, and various antenna resonant frequencies and frequency ratios can be obtained by properly adjusting the length of the meandering radiating metal line and the meandering pattern in which the meandering radiating metal line is formed, thereby satisfying all kinds of communication systems.
It is the other object of the present invention to provide a dual-band FR4 chip antenna to be suitable for using the SMT, so that the chip antenna can be massively produced, thereby lowering the cost for integrating with microwave circuits and further enhancing the product stability.
In accordance with the aforementioned objects of the present invention, the present invention provides a dual-band FR4 chip antenna, and the dual-band FR4 chip antenna comprises: an FR4 chip base made of an FR4 material; a meandering radiating metal line; and a connecting point, wherein the meandering radiating metal line is formed on at least two surfaces of the FR4 chip base, and is the major portion used by the antenna for radiating an electromagnetic wave, and the total length of the meandering radiating metal line is about {fraction (1/4 )}xcex (wavelength) of the central frequency in the antenna""s first operating band; and the connecting point is used for connecting the meandering radiating metal line to a signal transmission line, wherein the signal transmission line is used for conveying a signal for the system. The present invention can obtain dual-frequency operation with various frequency ratios by properly adjusting the length of the meandering radiating metal line and the meandering pattern in which the meandering radiating metal line is formed. Further, the dual-band FR4 chip antenna of the present invention is mounted on a microwave substrate having a ground surface used for connecting the signal ground terminal.